1. Field of the Invention
The present invention relates to a paper sheet punching and embossing machine.
2. Description of the Related Art
In known sheet punching and embossing machines, which are used for punching, tearing off, embossing and delivery of sheets of paper, cardboard, and other stock materials, it is known how to move the sheets with gripper cars into the individual stations of the machine. Grippers are secured on the cars and grab the sheets at a front end, while the gripper cars are moved on endless chains through the machine. With this type of movement of the sheets through the machine, continuous operation in the individual stations of the machine arranged one after the other is obtained. Since an impression of the gripper on the final punched and/or embossed sheet is undesirable, the marginal region at which the gripper grabs the sheet is separated from the finished sheet. This gripping margin is usually discarded at the end of the machine. Many different devices are known for separating the gripping margin from the sheet.
EP 0 586 876 B1 discloses a known a device in which a revolving cutting cylinder includes spaced apart blades, and a suction and blowing mechanism is arranged between the spaced blades. After the waste strip is separated by the blades arranged on the cylinder, the waste strip is held by a partial vacuum against the cylinder and transported away. The actual discarding of the waste strip occurs when, first, the suction is replaced by a blowing, and second, an exhaust hood is arranged above the cylinder, so that the waste strip is blown away from the cylinder by the blown air and attracted by the suction air of the exhaust hood.
DE 102 59 556 A1 discloses a known sheet punching and embossing machine of this kind, in which gripper cars are secured to revolving chains, and sheets are pulled through a sheet punching and embossing machine by grippers. The sheet punching and embossing machine includes a punching mechanism, a tear-off mechanism and a delivery mechanism. In a discarding station connected downstream, a gripping margin separated from the sheet is discarded. Discarding occurs by opening the grippers of the car, such that the gripping margin is dropped. To facilitate discarding of the gripping margin, brushes or wiper fingers are provided in the machine frame between the grippers.
Depending on the type of sheet being processed in the machine, a larger or smaller gripping margin will be wasted. A gripping margin is typically between two centimeters and five centimeters. Additionally, the gripping margin may also consist of a full-size sheet, from which the copy has been punched out. This gripping margin including a margin several centimeters thick, having the size of the complete sheet, also must be transported to the delivery station.
Especially when the gripping margin corresponds to a full-size sheet, the grip opening cam at the discarding station has to be adjusted to the gripping margin in order to eliminate the gripping margin as waste from the machine. For this, the machine must be retrofitted. With a normal gripping margin, one grip opening cam is attached in a first position and with a gripping margin equal to the size of the sheet a second grip opening cam is attached in a second position. For this, the ejection point has to be adjusted in a stepless manner, depending on the machine speed and the paper weight. Especially in the case of a gripping margin equal to the size of the sheet, this results in retrofitting costs, on the one hand, and a reduction in the machine speed, on the other, in order to eject a gripping margin equal to the size of the sheet from the machine.